Compressor valve of the slotted plate type

ABSTRACT

A compressor valve of the slotted plate type comprising: three plates stacked in face-to-face contact, each having a slot which is vertically aligned with the slots in the other two plates, the center plate slot being wider than the bottom and top plate slots; a pair of (right and left) slide bars mounted within the center plate slot for relative slidable movement laterally toward (and away from) each other to close and open the center plate slot and thereby respectively disconnect the bottom and top plate slots from (and reconnect them to) each other to close (and open) the valve; means yieldably urging the slide bars toward each other to close the valve; and means for communicating the fluid pressure in the bottom plate slot laterally in opposite (right and left) directions against the (right and left) slide bars in the center plate slot so that, if the device is operating as an inlet valve assembly, the pressure of the incoming fluid is effective to move the bars laterally away from each other on the suction stroke to open the inlet valve against the action of the spring means, whereas, if it is operating as an outlet valve assembly, the pressure of the outgoing fluid is effective to do ths same thing on the pressure stroke to open the outlet valve in the same way.

States Patent [11] 3,831,627 Aug, 27, 1974 CUMPRIESOR VALVE 0F THE SLO'TTED PLATE TYlPlE [75] Inventor: Paul C. Hanlon, Louisville, Ky. [73] Assignee: Dover Corporation, Washington,

[22] Filed: Mar. 14, 11973 [21] App]. No: 341,268

[52] US. Cl 1137/5121, 137/535, 137/538, 251/212 [51] Int. Cl F16k 15/02 [58] Field of Search 137/511, 512.1, 535, 538; 251/212 [56] References Qited UNITED STATES PATENTS 556,549 3/1896 Marichal 251/212 1,036,274 8/1912 Langer r 251/212 2,040,542 5/1936 Baker 137/535 2,406,662 8/1946 Burchett.. 251/212 X 3,595,521 7/1971 Lorentz.... 251/212 3,683,959 8/1946 Tsuji 137/538 X [57] ABSTRACT A compressor valve of the slotted plate type comprising: three plates stacked in face-to-face contact, each having a slot which is vertically aligned with the slots in the other two plates, the center plate slot being wider than the bottom and top plate slots; a pair of (right and left) slide bars mounted within the center plate slot for relative slidable movement laterally toward (and away from) each other to close and open the center plate slot and thereby respectively disconnect the bottom and top plate slots from (and reconnect them to) each other to close (and open) the valve; means yieldably urging the slide bars toward each other to close the valve; and means for communicating the fluid pressure in the bottom plate slot laterally in opposite (right and left) directions against the (right and left) slide bars in the center plate slot so that, if the device is operating as an inlet valve assembly, the pressure of the incoming fluid is effective to move the bars laterally away from each other on the suction stroke to open the inlet valve against the action of the spring means, whereas, if it is operating as an outlet valve assembly, the pressure of the outgoing fluid is effective to do ths same thing on the pressure stroke to open the outlet valve in the same way.

6 Claims, 13 Drawing Figures PATENTEDAUBZYIHM a. 831 a 2? sum 10': a5

FIG. I

CYLINDER 6 BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to valve assemblies of the superposed or stacked slotted plate type for use in compressors and the like.

2. Description Of The Prior Art The Mihalakis US. Pat. No. 3,109,451 dated Nov. 5, 1963 shows a compressor valve of the slotted plate type comprising: three plates (or equivalent) stacked in face-to-face relationship, each having a slot; and valve means for opening and closing the center plate slot to connect and disconnect the bottom and top plate slots respectively from and to each other and thereby close and open the valve. The compressor valve is typical of the prior art in that it provides a tortuous path for the flow of air through the valve. For example, with the valve arranged horizontally to accommodate an upward flow of air therethrough, the upwardly flowing air must also travel horizontally at some point during its flow through the valve means. This combination of vertical and horizontal flow necessarily increases the resistance of the valve to the flow of air therethrough. The Baker US. Pat. No. 2,040,542 is also typical.

SUMMARY OF THE INVENTION Objects Of The Invention The principal object of the invention is to provide a valve assembly having a valve mechanism which parts laterally to permit the air to flow forwardly through the assembly in one direction without deleterious lateral deflection and with a corresponding minimization of its resistance to the flow of air therethrough.

Another important object is to accomplish the principal object by a valve assembly which is of simple design, easy to make, assemble, and place in operation, effective in operation and not readily-subject to injury during operation.

Statement Of The Invention The objects of the invention are achieved in a slotted plate valve assembly by vertically (or longitudinally) aligning the slots of the assembly to permit a straightthrough flow of air through the assembly when the center plate slots are open and by arranging a valve mechanism in the center plate slot to open in a direction proceeding horizontally (or laterally) relative to the flow of air. In the preferred embodiment, a pair of bars is mounted in the center plate slot for movement toward and away from each other to close and open the center plate slot and thereby respectively connect and disconnect the bottom plate slot from the top plate slot so as to close and open the valve. Preferably the plates come together at the center of the longitudinal (say vertical) passageway provided by all three slots when the valve is open.

With this arrangement, smooth air flow conditions longitudinally (say upwardly) through the valve are promoted and turbulence or other energy consuming factors are minimized with a corresponding decrease in the resistance to the flow of air through the valve when it is open. Simplicity in structure and operation is promoted by the use of springs to urge the bars yieldably into their closed position and by the use of chamfers extending obliquely across the bottom corners of the adjacent edges of the slide bars (along the bottom face of the slotted center plate) so as to facilitate the appli cation of lateral or horizontal bar-separating pressure to the bars of the inlet valve on the suction stroke and to the bars of the outlet valve on the compression stroke.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated in the accompanying drawings wherein:

FIG. 1 is a vertical cross-sectional view of a compressor having inlet and outlet valve assemblies constructed in accordance with the present invention;

FIG. 2 is en enlarged view showing, in vertical crosssection, one pair of identical inlet and outlet valve assemblies of FIG. l in vertically spaced relationship;

FIG. 3 is a broken top plan view (of smaller scale than FIG. 2) showing the bottom plate of the lower valve assembly, this view corresponding to one taken along the left half of line 33 of FIG. 2;

FIG. 4 is a top plan view (on the scale of FIG. 3) showing the top plate of the lower valve assembly, this view corresponding to one taken along line 4-4 of FIG. 2 but omitting the underlying parts;

FIG. 5 is a partly broken top plan view (on the scale of FIG. 2) showing the spacer plate of the upper valve assembly and its valve means, this view corresponding to one taken along the right half of line 55 of FIG. 2;

FIGS. 6 and 7 are inlet face and inner edge elevational views of one of the transversly slidable bars in the valve means of FIG. 5, the edge view of FIG. 6 corresponding to one taken along line 6-6 of FIG. 5;

FIG. 8 is a slide bar section taken along line 88 of FIG. 6;

FIG. 9 is an enlarged fragmentary view indicating the upward flow of air through three vertically aligned open slots, one slot in each of the three superposed plates in the lower valve assembly of FIG. 2;

FIG. 10 is an enlarged sectional view of a fragmentary portion of two closed slide bars, this view showing the interspace between opposed edge faces of the bars;

FIG. 11 is an enlarged sectional view of fragmentary portion of the lower and upper valve assemblies at the beginning of the suction stroke;

FIG. 12 is an enlarged sectional view of a fragmentary portion of the same lower and upper valve assemblies at the beginning of the pressure stroke; and

FIG. 13 is a perspective view of a modified pair of valve mechanism bars which are flexed into a valveopen position.

DESCRIPTION OF THEPREF ERRED EMBODIMENT Figs. l-9

F IG. 1 shows a compressor 1 which, between bottom and top inlet andoutlet openings 2 and 3, respectively, conventionally comprises: a piston 4, an inlet assembly 5, cylinder chamber 6 and outlet valve assembly 7 on the left side of the piston; an inlet valve assembly 5, cylinder chamber 6' and an outlet valve assembly 7 on the right side of the piston; and four crabs 8, one for each valve assembly, each crab forcing its valve assembly to seat tightly against a seat-receiving shoulder on the cylinder of the compressor ll. As is well known to those skilled in the art: when piston 4 moves to the right, a stream of incoming supply fluid (any of a range of gases including air) is sucked through compressor inlet 2 and the left inlet valve assembly into left cylinder chamber 6 while a stream of outgoing pressurized fluid is forced out of right cylinder chamber 6 'through right outlet valve assembly 7 and compressor outlet 3; and, when piston 4 moves to the left, a stream of incoming supply fluid is sucked through compressor inlet 2 and right inlet valve assembly 5 into right cylinder chamber 6 and while a stream of outgoing pressurized fluid is forced out of left cylinder chamber 6 through left outlet valve assembly '7 and compressor outlet 3.

FIG. 2 shows, in enlarged vertical cross-section, one inlet valve assembly 5 arranged under one identical outlet valve assembly 7. The lower inlet valve assembly 5 conventionally comprises three superposed slotted plates and retainer pins as follows: a 1st slotted gridlike bottom plate member 10 having horizontally spaced ribs 11 forming slots 12; a 2nd slotted grid-like top plate member 15 having horizontally spaced ribs 16 containing openended bores 16A and forming slots 17, the 2nd member being vertically spaced from the 1st member; an interposed slotted grid-like spacer plate 20 having horizontally spaced ribs 21 forming slots 22; and a suitable number of vertical aligning and retaining pins 25 for each valve assembly, these pins fixing the relative location of the seat member 10, guard member 15 and the spacer plate 20.

The upper outlet valve assembly 7 is identically constructed; hence, its corresponding parts are given corresponding numbers 100 units higher, viz: bottom plate 110, ribs 1 l1 and slots 112; top plate 115, ribs 116, and slots 117; spacer plate 120, ribs 121 and slots 122; and retainer pins 125. The same is true of lower and upper valve assemblies 5 and 7.

In accordance with my invention, the lower inlet valve assembly 5 is arranged as follows: each plate, as shown, has four slots, and each slot in one plate has a corresponding slot in each of the other two plates; the centers of each series of corresponding slots 12, 17 and 22 are vertically aligned with each other; each inlet slot 12 of the bottom plate converges upwardly toward the corresponding slot 22 of the interposed spacer plate; each outlet slot 17 of the top plate diverges upwardly away from the corresponding slot 22 of the spacer plate; and each spacer plate slot 22 is not only made wider than the adjacent inner end of the corresponding slots 12 and 17 on the top and bottom plates but are wide enough to accommodate the valve mechanism of my invention.

The upper inlet valve assembly 7 is identically arranged.

A valve mechanism is provided for each slot 22 in the lower inlet valve assembly. Each valve mechanism comprises slide bars, bar-closing springs and baropening means as follows: a pair of flat slide bars 30, 31 mounted in its plate slot 22 for slidable valve-closing movement toward and valve-opening movement away from each other, said bars having adjacent inner perimetrical edges 31 which are in flush engagement with each other when the valve is closed; spring means compressing the bars 30, 31 yielding together to close the plate slot 22 of the valve, the spring means shown including a pair of U-shaped springs 32, one at each end of said pair of slide bars 30, 31, each U-shaped spring 32 embracing the adjacent end of the slide bars 30, 31 in a manner such that the springs 32 at opposite 30, 31 into flush slot-closing engagement with each other; and means (chamfers 34,35) for communicating the fluid pressure along the upstream face of the slide bars 30, 31 of each valve mechanism laterally against either or both of their adjacent inner vertical perimetrical edges 30', 31 (or the equivalent thereof) so that the incoming fluid moves the yieldably closed bars 30,31 laterally away from each other on the suction stroke to open the inlet valve against the action of the associated springs 32. We assume that the slide bars are held closed by a force equal to the psi of the cylinder fluid on the bars adjacent the springs 32 plus the spring pressure which can be say l /zpsi for example. The cylinder fluid pressure along the downstream face of top plate 15 is communicated to the bars 30, 31 through bores 16A. The compressor fluid pressure along the downstream face of the top plate 115 is communicated to the bars 30, 31 through bores 116A.

The valve mechanism provided for each slot 122 in the upper inlet valve assembly is identical in construction and operation; hence, its corresponding parts are given corresponding numbers units higher, viz: slide bars 130, 131; adjacent inner perimetrical edges 130, 131' of slide bars 130, 131, U-shaped springs 132, chamfers 134 and 135.

Since the operation of my inlet and outlet valve assemblies should be clear from the foregoing, it should suffice to say that, as can be understood from FIG. 2: the suction stroke creates a low fluid pressure in bores 16A and slots 17 of the lower inlet valve assembly and this renders the higher fluid pressure, in the inlet slots 12 of that same lower assembly, effective, in pressing against the chamfers 34 and 35 of each of the valve slide bars 30, 31, to spread those slide bars apart to open the lower valve assembly and thereby permit the flow of fluid into the cylinder chamber 6. At the same time, this same suction stroke creates a low fluid pressure in the bottom plate slots 112 of the upper valve assembly. This renders the higher fluid pressure along the downstream face of the upper (downstream) outlet valve assembly 7 effective, in that portion of slot 122 which surrounds the perimeter of the' slide bars, to push those bars toward each other and thus close the valve, Spring 132 also helps in this closing operation. It also renders that same pressure effective in the outlet slots 117 of that assembly to press downwardly against the slide bars 130-131 without any operative effect other than to urge them downwardly toward the bottom plate of the upper valve assembly. As a consequence, during the suction stroke, fluid can flow into cylinder 6 only through the lower valve assembly. At the end of the suction stroke, the springs 32 become effective to close slide bars 30, 31 of the lower valve assembly.

On the pressure stroke, the rising pressure of the fluid within the cylinder 6 along the downstream face of the lower (upstream) inlet valve assembly becomes effective, in that portion of slot 22 which surrounds the perimeter of the slide bars, to hold those valve slide bars 30, 31 in the closed position. It also renders that same pressure effective in the outlet slots 17 of that lower valve assembly to urge the valve bars 30, 31 downwardly toward the bottom plate 10 of the lower valve assembly 5. As a consequence, during the pressure stroke, fluid can flow out of cylinder 6 only through the upper valve assembly. In the upper valve assembly 7,

the same rising fluid pressure acts on chamfers 134-135 and ultimately is effective to force slide bars 130, 131 apart so as to permit the fluid to flow outwardly from cylinder 6 upwardly through the upper valve assembly 7.

While the actions, respectively occasioned by lowering suction pressure and rising positive pressure in cylinder 6, occur, the reverse of those actions contemporaneously occurs in cylinder chamber 6'. In other words, the suction stroke for cylinder chamber 6 is the pressure stroke for cylinder chamber 6' while the pressure stroke for cylinder chamber 6 is the suction stroke of cylinder chamber 6'. The actions are the same, i.e., air is pulled in through the lower valve assembly 5 during the suction stroke and then pressurized and forced out through the upper valve assembly 7 during the pressure stroke..As seen in FIG. 9, smooth air flow conditions are promoted in all such actions by the direct longitudinally upward flow of fluid through each valve assembly and its valve mechanisms.

In order to permit the spacer-plate-slot slide bars 30, 31 and 130, 131 to slide laterally toward and away from each other, the spacer plates must be sufficiently thicker than the slide bars to provide the requisite clearance. Accordingly, it will be understood that the construction shown in FIGS. 1-9 has a sufficient clearance which may be on the order of plus or minus 0.003 inches.

FIGS. 10-12 In the lower reciprocating frequencies of the piston 4, it is always desirable but it may not be absolutely necessary to use the chamfers 34, 35 and 134, 135 in the bottom and top valve assemblies 5 and 7. With adequate stroke time, the fluid pressure can penetrate the interface space between (or at the common boundary of) the closed slide bars sufficiently to provide the requisite lateral bar-opening pressure.

For example, in the fragmentary view of FIG. 10, a fragment of the interface space between (or at the common boundary of) the closed slide bars 230, 231, which do not have chamfers, is magnified to show that the opposed edge faces of the slide bars, which normally appear to the naked eye to be in perfectly smooth flush engagement, are actually characterized by microscopic surface irregularities providing space or spaces between opposed interface surfaces 230, 231. When the fluid pressure, applied along the upstream boundary of this interspace, is higher than that along the downstream face thereof, the higher pressure fluid slowly penetrates the interface space and builds up a rising positive pressure in that space. The ultimate magnitude of this pressure depends upon stroke time, among other things; hence, the buildup will become sufficient to open the valve if given enough time during a given stroke.

This interface space action occurs in the valve structure shown in FIGS. 11-12. Here, the three superposed plates in the bottom and top valve assemblies 5 and 7 are identical to the three superposed plates in the bottom and top valve assemblies 5 and 7 of FIG. 2, except for non-meaningful dimensional variations. The same is true of the valve mechanisms, in the spacer-plate slots of the bottom and top valve assemblies, except that the chamfers 34, 35 and 134i, 135 in the FIG. 2 mechanisms are omitted from the FIG. 11-12 mechanisms. It will also be noted that the scale of the FIG. 11-12 drawings is magnified in order to show that the slotted spacer plates are thicker than their respective slide bars, the clearance resulting from that difference being magnified for the sake of clarity.

Now, with respect to conditions under the suction stroke indicated in FIG. 11, we assume: that the inlet pressure PX has a magnitude of I50 psi; that the springs 32, 132 apply a pressure of 1.5 psi; that at the beginning of the suction stroke, the cylinder pressure P- has a magnitude of 50 psi which, in combination with the spring pressure, presses all slide bars together with a force equal to 51.5 psi; and that, as the suction stroke proceeds, the cylinder pressure quickly drops to 15.0 psi at an intemiediate point of the suction and tends to drop below 13.5 psi substantially before it reaches the end of the suction stroke. When the cylinder pressure starts to drop more than 1.5 psi below the inlet pressure of 15 psi, the inlet fluid, penetrating the interspace between the slide bars, should build up a pressure sufficient to open the valve, if the remaining suction stroke time permits. When the valve opens, the incoming fluid quickly raises the cylinder pressure P- to a value equal to Px at the end of the suction stroke. Now the inlet valve closes.

Now, with respect to the pressure stroke conditions indicated in FIG. 12, we assume: that the outlet pressure Py has a magnitude of 50.0 psi; and that, at the beginning of the pressure stroke, the cylinder pressure P, which we will now call P+ in order to distinguish the pressure of the suction stroke from that of the pressure stroke, has an initial magnitude of 15.0 psi and that, as the pressure stroke proceeds, the cylinder pressure rises to 50 psi at an intermediate point of the pressure stroke and tends to rise above 51.5 psi substantially before it reaches the end of the pressure stroke. Again, when the cylinder pressure starts to rise more than 1.5 psi above the 50 psi outlet pressure, the cylinder fluid, penetrating the interspace between the slide bars, should build up a pressure operating against the resistance of spring 132 and pressure Py and ultimately sufficient to open the valve if the remaining pressure stroke time permits. When the valve opens, the outgoing fluid causes the cylinder pressure P+ to equal the outlet pressure Py at the end of the: suction stroke. Now the outlet valve closes.

From the foregoing, it will be evident that without chamfers, the time factor restricts the use of the valve mechanism to a range of reciprocating frequencies lower than that which can be employed when chamfers are used. With chamfers, there is a fast buildup of lateral valve-opening pressure between chamfers. Without chamfers, there is a slower buildup of valveopening pressure in the interspace between the slide bars. Finally, it will be understood that the interspace action may also occur in the embodiment shown in FIGS. 2-9.

It will be understood: that, while two cooperating slide bars mounted for lateral movement toward and away from each other, comprise a very desirable form of valve bar means, only one bar is essential for the valve bar means since, for slit-closing and opening purposes, it can be mounted within a spacer plate slot for lateral movement toward and away from a fixed cooperating surface of the spacer plate itself; and that the chamfer and microscopic surface irregularities of a given slide bar constitute a means on said bar or valve bar means for directing fluid pressure, along and against one major face of the spacer plate, laterally open position.

MODIFICATION FIG. 13

An equivalent valve mechanism may be in the form of resilient back-to-back bars 440, 441 shown in FIG. 13. These bars normally are biased into a back-to-back valve-closed position but, with their opposite ends restrained from appreciable lateral separating movement, they bow or flex laterally away from each other to open the valve under requisite laterally applied penetrating fluid pressure in the interspace or in the chamfer space or in both spaces.

It will be appreciated that, as applied to FIG. 2, my improved upstream valve mechanism comprises: A. three stationary transverse plate-like structures including a transverse upstream outer structure 10 having an upstream outer face and a down stream inner flat face and, through its thickness, a transversely elongate opening 12 terminating, at its inner flat face, in a long narrow slot, a transverse downstream outer structure 15 having an upstream inner flat face and a downstream outer face and, through its thickness, a transversely elongate opening 17 terminating, at its inner flat face, in a long narrow slot, and a center spacer plate structure 20 having upstream and downstream inner flat faces and, through its thickness, a transversely-elongate laterally wide slot 22 which is substantially wider than said slot in the inner face of at least one of the other structures, the perimeter of said wide slot 22 being characterized by transversely-elongate side walls and laterally short end walls; B. means securing said three plates together in flat face-to-face contacting relationship with their slots in longitudinal alignment; C. bar valve means, including at least one laterally-narrow bar, say 30, having a perimeter characterized by oppositely disposed outer and inner transversely elongate side walls and laterally-short end walls, said bar being positionable within said wider spacer plate slot 22 for relative back-and-forth lateral or sidewse movement across at least a part of the width thereof, between a slot open position, wherein all three structures cooperate to permit a substantially unobstructed unidirectional longitudinal flow of fluid proceeding in the upstream to downstream direction, and a laterally spaced slot-closed position, wherein said bar shuts off said longitudinal flow; D. yieldable means 32 arranged in said wide slot 22 to urge said bar 30 laterally sidewise in one direction toward said slotclosed position; and E. valve opening means 34 for causing laterally directed fluid pressure, derived from that exerted longitudinally against the upstream face of said bar means and one of said outer structures, to be directed sidewise against the inner perimetric side wall of said bar 30 to urge it sidewise in the opposite direction toward said slot-open position, said valve opening means being operative to open said valve when the high-to-low pressure drop across said bar valve means in the direction of fluid flow rises to a value at which said lateral sidewise pres sure overcomes said yieldable means.

The foregoing is true of my improved downstream valve mechanism 7.

Having described my invention 1 claim:

1. An improved valve for use in compressors and the like comprising:

A. three stationary transverse plate-like structures including 1. a transverse upstream outer structure having an upstream outer face and a downstream inner flat face and, through its thickness, a transversely elongate opening terminating at its inner flat face in a long narrow slot, I

2. a transverse downstream outer structure having an upstream inner flat face and a downstream outer face and, through its thickness, a transversely elongate opening terminating at its inner flat face in a long narrow slot, and

3. a center spacer plate structure having upstream and downstream inner flat faces and, through its thickness, a transversely-elongate laterally-wide slot which is substantially wider than said slot in the inner face of at least one of the other structures, a. the perimeter of said wide slot being characterized by transversely-elongate side walls and laterally short end walls;

B. means securing said plates together in flat face-toface contacting relationship with their slots in longitudinal alignment;

C. bar valve means, including at least one laterally narrow bar having a perimeter characterized by oppositely disposed outer and inner transverselyelongate side walls and laterally short end walls, 1. said bar being positionable within said wide spacer plate slot for relative back-and-forth lateral of sidewise movement, across at least a part of the width thereof, between a slot-open position, wherein all three structures cooperate to permit a substantially unobstructed unidirectional longitudinal flow of fluid proceeding in the upstream to downsrtream direction, and a laterally spaced slot-closed position wherein said bar shuts off said longitudinal flow;

D. yieldable means arranged in said wide slot to urge said bar laterally sidewise in one direction toward said slot-closed position; and

E. valve opening means for causing laterally directed fluid pressure, derived from that exerted longitudinally against the upstream face of said bar means and the adjacent upstream outer structure, to be directed sidewise against the inner perimetric side wall of said bar to urge it sidewise in the opposite direction toward said slot-open position,

1. said valve means being operative to open said valve when the high-to-low pressure drop across said bar valve means in the direction of fluid flow rises to a value at which said lateral sidewise pressure overcomes said yieldable means.

2. The valve of claim 1 wherein:

A. said one bar is a slide bar; and

B. said yieldable means is located in the wide slot space between and longitudinally spaced inner faces of the said upstream and downstream outer structures and between the laterally spaced outer perimetric side wall of said slide bar and the adjacent perimetric side wall of said wide slot.

3. The valve of claim 2 including:

A. means communicating the pressure along the downstream outer face of the transverse downstream outer structure from that outer face through that structure to the wide slot space between the outer perimetric side wall of said one slide bar and the adjacent side wall of said wide slot.

4. The valve of claim 2 wherein: A. said bar valve means includes another like lateral- 5. The valve of claim 4 including:

A. means communicating the fluid pressure along the downstream outer face, of the transverse downstream outer structure, from that outer face through that structure to the wide slot space between the outer perimetric side wall of said other slide bar and the adjacent side wall of said side slot.

6. The valve of claim 2 wherein:

A. said valve opening means include a chamfer on said one bar along the upstream intersection of its inner transverselyelongate side wall with its upstream face.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION latent NO. 3 1 627 Dat d Ag, 27. 1974 Inv nfl fl Paul C. Hanlon It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

SPECIFICATION In the ABSTRACT, 2nd line from the bottom, change 'ths" to v m the Col. 1, line 18, change "The" to This I Col. 3, line 32, after "ribs 116," insert bores 116A Col. 6, line 13, after "auction" insert stroke Col. 8, claim 1, line 30, before "sidewise" change "of" I to or claim 1-, line 35, correct spelling of "downstream" claim 1, line 48, before "means" insert opening Col. 8, claim 2, line 56, before "longitudinally" change "and" to the Col. 10, claim 5, line 7, change "side slot." to wide slot.

Signed and sealed this 12th day of November 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents 

1. An improved valve for use in compressors and the like comprising: A. three stationary transverse plate-like structures including
 1. a transverse upstream outer structure having an upstream outer face and a downstream inner flat face and, through its thickness, a transversely elongate opening terminating at its inner flat face in a long narrow slot,
 2. a transverse downstream outer structure having an upstream inner flat face and a downstream outer face and, through its thickness, a transversely elongate opening terminating at its inner flat face in a long narrow slot, and
 3. a center spacer plate structure having upstream and downstream inner flat faces and, through its thickness, a transversely-elongate laterally-wide slot which is substantially wider than said slot in the inner face of at least one of the other structures, a. the perimeter of said wide slot being characterized by transversely-elongate side walls and laterally short end walls; B. means securing said plates together in flat face-to-face contacting relationship with their slots in longitudinal alignment; C. bar valve means, including at least one laterally narrow bar having a perimeter characterized by oppositely disposed outer and inner transversely-elongate side walls and laterally short end walls,
 1. said bar being positionable within said wide spacer plate slot for relative back-and-forth lateral of sidewise movement, across at least a part of the width thereof, between a slotopen position, wherein all three structures cooperate to permit a substantially unobstructed unidirectional longitudinal flow of fluid proceeding in the upstream to downsrtream direction, and a laterally spaced slot-closed position wherein said bar shuts off said longitudinal flow; D. yieldable means arranged in said wide slot to urge said bar laterally sidewise in one direction toward said slot-closed position; and E. valve opening means for causing laterally directed fluid pressure, derived from that exerted longitudinally against the upstream face of said bar means and the adjacent upstream outer structure, to be directed sidewise against the inner perimetric side wall of said bar to urge it sidewise in the opposite direction toward said slot-open position,
 1. said valve means being operative to open said valve when the high-to-low presSure drop across said bar valve means in the direction of fluid flow rises to a value at which said lateral sidewise pressure overcomes said yieldable means.
 2. a transverse downstream outer structure having an upstream inner flat face and a downstream outer face and, through its thickness, a transversely elongate opening terminating at its inner flat face in a long narrow slot, and
 2. The valve of claim 1 wherein: A. said one bar is a slide bar; and B. said yieldable means is located in the wide slot space between and longitudinally spaced inner faces of the said upstream and downstream outer structures and between the laterally spaced outer perimetric side wall of said slide bar and the adjacent perimetric side wall of said wide slot.
 3. The valve of claim 2 including: A. means communicating the pressure along the downstream outer face of the transverse downstream outer structure from that outer face through that structure to the wide slot space between the outer perimetric side wall of said one slide bar and the adjacent side wall of said wide slot.
 3. a center spacer plate structure having upstream and downstream inner flat faces and, through its thickness, a transversely-elongate laterally-wide slot which is substantially wider than said slot in the inner face of at least one of the other structures, a. the perimeter of said wide slot being characterized by transversely-elongate side walls and laterally short end walls; B. means securing said plates together in flat face-to-face contacting relationship with their slots in longitudinal alignment; C. bar valve means, including at least one laterally narrow bar having a perimeter characterized by oppositely disposed outer and inner transversely-elongate side walls and laterally short end walls,
 4. The valve of claim 2 wherein: A. said bar valve means includes another like laterally-narrow bar arranged in said wide slot for lateral movement toward and away from said one slide bar for slot-closing and slot-opening purposes respectively; and B. said yieldable means includes resilient means in said wide slot, between the longitudinally spaced inner faces of said upstream and downstream outer structures and between the laterally spaced outer perimetric side wall of said other slide bar and the adjacent perimetric side wall of said wide slot, to urge said other slide bar laterally toward said one slide bar and said slot-closed position.
 5. The valve of claim 4 including: A. means communicating the fluid pressure along the downstream outer face, of the transverse downstream outer structure, from that outer face through that structure to the wide slot space between the outer perimetric side wall of said other slide bar and the adjacent side wall of said side slot.
 6. The valve of claim 2 wherein: A. said valve opening means include a chamfer on said one bar along the upstream intersection of its inner transversely elongate side wall with its upstream face. 